1. Field of the Invention
The present invention relates generally to turbine airfoils, and more specifically to showerhead cooling hole arrangements for turbine airfoils.
2. Description of Related Art
A gas turbine engine includes a turbine section with a plurality of stages of stationary vanes and rotary blades to extract mechanical energy from a hot gas flow passing through the turbine. The gas turbine engine efficiency can be increased by providing for a higher temperature of the gas flow entering the turbine. The temperature entering the turbine may be limited to the first stage vanes and rotor blades ability to withstand the high temperature.
One method of allowing for higher temperatures than the material properties of the first stage vanes and blades would allow is to provide for cooling air passages through the airfoils. Since the cooling air used to cool the airfoils is generally bled off from the compressor, it is also desirable to use a minimum amount of bleed off air in order to improve the efficiency of the engine.
The hottest part of the airfoils is found on the leading edge. Despite the variety of leading edge region cooling configurations in traditional blades and vanes, further improvement is always desirable in order to allow the use of higher operating temperatures and reduced cooling air flow rates through the airfoils, as well as to minimize manufacturing costs. The present disclosure provides a solution for this need.